Ventilation requirements on a hipped roof (Dormont: houses, crawl space, roofing)

[Doowlle34]

I tried a version of this question on another online forum, and didn't get great results. However, I'm interested in any feedback from folks who may have replaced a "hipped" roof lately, and in particular, what your roofer may have recommended regarding ventilation. Currently, our roof has updated soffit ventilation that is in pretty good shape, but just two box vents on either side of the small "ridge". In getting quotes on our roof, some roofers just want to duplicate the current ventilation; however, one roofer has recommended that we add "hip ventilation" along all four hips of our roof. I'm not necessarily so much concerned with the cost, as the hip ventilation is only adding $1,000 to the project, and the roofer indicated that they will do the project with or without the hip ventilation. However, the roofer uses an Owens-Corning roofing system and per the roofer (and as confirmed by Owens), Owens will only grant an extended warranty on the shingles if they are installed with adequate ventilation, per Owens' requirements. So, I guess my biggest concern is that, in looking around Dormont, which mostly consists of four square houses with hipped roofs, I am not necessarily seeing anyone with "hip vents". From some online searching, it does appear that hip vents (especially the modern iterations) are fairly robust products and are generally designed to prevent rain/snow from getting into the attic/crawl space, even in extreme conditions (i.e., high/horizontal winds, with rain and/or snow). Nevertheless, I'm just not seeing these hip vents on many houses, so I figured I would reach out to the broader community to see if you had any input.

Thanks!

[PghYinzer]

Originally Posted by Doowlle34

I tried a version of this question on another online forum, and didn't get great results. However, I'm interested in any feedback from folks who may have replaced a "hipped" roof lately, and in particular, what your roofer may have recommended regarding ventilation. Currently, our roof has updated soffit ventilation that is in pretty good shape, but just two box vents on either side of the small "ridge". In getting quotes on our roof, some roofers just want to duplicate the current ventilation; however, one roofer has recommended that we add "hip ventilation" along all four hips of our roof. I'm not necessarily so much concerned with the cost, as the hip ventilation is only adding $1,000 to the project, and the roofer indicated that they will do the project with or without the hip ventilation. However, the roofer uses an Owens-Corning roofing system and per the roofer (and as confirmed by Owens), Owens will only grant an extended warranty on the shingles if they are installed with adequate ventilation, per Owens' requirements. So, I guess my biggest concern is that, in looking around Dormont, which mostly consists of four square houses with hipped roofs, I am not necessarily seeing anyone with "hip vents". From some online searching, it does appear that hip vents (especially the modern iterations) are fairly robust products and are generally designed to prevent rain/snow from getting into the attic/crawl space, even in extreme conditions (i.e., high/horizontal winds, with rain and/or snow). Nevertheless, I'm just not seeing these hip vents on many houses, so I figured I would reach out to the broader community to see if you had any input.

Thanks!

Is a hip vent also a ridge vent? I had my Brookline four square(ish) roof replaced a few years ago and they added them at least on the main hip but I cant remember if they were added to the dormers or not.

[Doowlle34]

My understanding is that, while a hip vent is similar to a ridge vent, it is an alternative to a ridge vent in situations where, as you have with a "hipped roof," the "ridge" is not long enough to provide adequate ventilation. So, the hip vent product looks similar to the ridge vent product, and the concept is the same. We do have one large dormer in the front and one in the back, but (my understanding is that) the roofer is not recommending any ventilation on the hips of the dormers, but only on the (I guess) "main" hips (that is, all four of them).

[Wells5]

You can install a roof turbine ventilator or a powered roof fan vent. They do a good job of cooling the attic but cutting into the roof can cause problems.

[PghYinzer]

Originally Posted by Doowlle34

My understanding is that, while a hip vent is similar to a ridge vent, it is an alternative to a ridge vent in situations where, as you have with a "hipped roof," the "ridge" is not long enough to provide adequate ventilation. So, the hip vent product looks similar to the ridge vent product, and the concept is the same. We do have one large dormer in the front and one in the back, but (my understanding is that) the roofer is not recommending any ventilation on the hips of the dormers, but only on the (I guess) "main" hips (that is, all four of them).

Hmmm I dont think I know my roofing terminology. Is the hip the where the four sides of the roof meet? I have a front dormer that peaks at the same height as the main hip, and there is definitely a vent along the top of that. The second dormer off to the side, I am not sure if it runs out there or not.

[Doowlle34]

Originally Posted by PghYinzer

Hmmm I dont think I know my roofing terminology. Is the hip the where the four sides of the roof meet? I have a front dormer that peaks at the same height as the main hip, and there is definitely a vent along the top of that. The second dormer off to the side, I am not sure if it runs out there or not.

Here's perhaps an easier way -- if you view your hipped, four square home roof as basically a triangle in the front and a triangle in the back (and, frankly, triangles or maybe trapezoids on the sides as well, but let's ignore those for now) -- the hips are basically the four "legs" or non-hypotenuses of those two triangles. Stated another way, the hips are the slashes in this award-worthy diagram: /_\.

[Moby Hick]

I Can't Believe It's Not CAD.

[PghYinzer]

Originally Posted by Doowlle34

Here's perhaps an easier way -- if you view your hipped, four square home roof as basically a triangle in the front and a triangle in the back (and, frankly, triangles or maybe trapezoids on the sides as well, but let's ignore those for now) -- the hips are basically the four "legs" or non-hypotenuses of those two triangles. Stated another way, the hips are the slashes in this award-worthy diagram: /_\.

Yep no vents on those on my house.

[guy2073]

Spray foam the underside, problem permanently solved

[Doowlle34]

Interestingly enough, I did schedule a consult with Mincin insulation for this Wednesday. Our roof is probably nearing the end of its useful life, but it is very steep, so we've been told that we can likely get a bit longer out of it, if necessary. The only "issue" we've had is that, in February 2018, when we had a super cold spell, we got a few drips of water from the heating vent in our bathroom ceiling (and there is an area on the ceiling where the paper-thin, outer layer of the ceiling drywall was starting to droop -- i "smoothed" this drooping part back against the ceiling and it hasn't given me a problem since then). In any event, I thought maybe we had an ice damn form on the roof, and we had some water sitting up there for a bit and it seeped through. However, more recently, I thought maybe warm air was escaping from the second floor, which then condensed in the crawl space in the attic, and that this maybe caused the minor moisture issues.